If your bid was placed before a live auction you can go to the lot in the catalog and select "Delete your bid" located to the right of "Edit your bid" as shown below.
If your bid was placed during a live auction but the auctioneer has not yet offered that lot, you can find the lot under your "Autobids" tab located to the right in your bidding applet. Simply select the lot you would like to remove the bid for and choose "Delete".
If your bid was placed before a competitive live auction the bid cannot be decreased or removed before the auction starts. Once the auction has gone live, you can amend or delete the bid in the live bidding applet.
If your bid was a max bid placed in a timed auction you can amend the bid by placing a new max bid. The new max bid placed can be lower than your current max bid but cannot be lower than the current bid.
EX: If your max bid is 100 and the current bid is 50, you can change your max bid to a minumum if 50.
If you have placed a max bid on a lot by accident, and would like to remove it completely, you will need to contact the auctioneer directly to see if they would be willing to remove the bid from the lot.
If you have placed a bid and won a lot in a live auction by accident you will need to contact the auctioneer immediately to see if they would be willing to remove the bid from the lot.